Emotional Speech Synthesis
Since I am working with audio synthesis projects, I can suggest you to go through the recently released paper "MelNet: A Generative Model for Audio in the Frequency Domain", in this architecture human like speech is synthesized, I think this might be better than WaveNet where the generated audio does contain robotic nature, I think this will definitely help you with Emotional speech synthesis as it generates human-like voices.
You can check for online demos as well.

Demo

Here Is the Paper!

Related YouTube Video 

Hope this helps!